1. Field of the Invention
Applicant's invention relates generally to steam engines modified to increase operational efficiency. More specifically, the invention pertains to a new and improved steam engine with an internally fired generator that makes use of exhaust condensate as the primary source of steam, this steam in turn being used to reduce emissions and supplement the power produced by combustion.
2. Background Information
The low operational efficiency of conventional internal combustion engines derives from exhaustion of waste heat to the atmosphere along with heat lost through the cooling system. Steam engines lose most of their operational efficiency through the energy consumed by converting water to steam.
U.S. Pat. No. 1,424,798 discloses an explosive engine wherein steam is produced by mixing preheated water directly with a portion of the combustion gases that have been diverted from the power stroke of the piston. This steam is later readmitted to the same cylinder after the combustion gas has been completely exhausted and is allowed to expand to produce a steam driven power stroke. U.S. Pat. No. 1,424,798 describes a two-cycle engine modified to operate in a four cycle manner. The modification involves complex and costly construction and retains the limitations and disadvantages of conventional two-cycle engines. Moreover, operational efficiency is reduced significantly due to power lost by diverting combustion gases from the power stroke to produce steam.
U.S. Pat. No. 4,783,963 attempts to improve efficiency of the internal combustion engine by grouping cylinders into pairs, each pair containing a combustion driven piston and a steam driven piston. Combustion is initiated in the first cylinder, wherein the burning gases are forced through a common transfer valve (during the exhaust cycle) into the second cylinder, where hot water is injected to produce steam and power the second cylinder through an exhaust cycle. The system of U.S. Pat. No. 4,783,963 has the disadvantage of friction/power losses associated with the extra piston for steam driven power.
In an attempt to combine both steam and combustion power for the operation of a single piston, U.S. Pat. No. 4,433,548 utilizes a complicated system of valves and pumps to condense water from exhaust gases and reintroduce the condensate for a conversion to steam. Separate power and steam strokes drive a single piston in the same direction. Such a system provides the advantages of both steam and combustion engines on alternating strokes, but also provides widey varying torque between each stroke at low speeds.
An invention which provides steam during the power stroke of the engine is disclosed by U.S. Pat. No. 4,122,803. However, the device is directed toward the installation of a boiler ring around the periphery of each cylinder head in a modified conventional internal combustion engine.
Another method of combining internal combustion and steam power is described in U.S. Pat. No. 4,706,462. In this invention, the piston is either driven purely by internal combustion or steam. A water jacket surrounds the cylinder head and when enough heat is gathered to produce steam, the ignition mechanism for the piston is deactivated and a steam valve is opened to power the piston using the newly generated steam. When there is no longer sufficient heat for steam generation, the ignition system for the piston is reactivated to power the piston by combustion and create more heat for additional steam generation. The system of U.S. Pat. No. 4,706,462 may also result in widely varying torque availability, as the piston is alternately powered by combustion and steam.
U.S. Pat. No. 4,976,226 contemplates inserting an additional two cycles of steam power within the traditional two or four cycle operational sequence of the internal combustion engine. Instead of the usual exhaust cycle, the exhaust valve is held closed while water is injected into the cylinder near the end of the power stroke so that a new compression stroke is added in place of what would have been the exhaust stroke. As a result, heat accumulated in the walls of the cylinder during the course of the preceding power stroke is transmitted to the cooled and compressed combustion products and the injected water mist so that the resulting steam produces an additional power stroke. The exhaust valve is then opened during the sixth stroke so that the newly expanded gases may be forced out of the cylinder. This system has the efficiency disadvantage of using a power stroke to generate steam.
U.S. Pat. Nos. 5,125,366 and 5,261,238 are both concerned with the timing of water injection for combustion engines. U.S. Pat. No. 5,125,366 discloses a water injection system that is computer controlled. Injection in this system is responsive to a multiplicity of sensors which monitor conditions at various points of a conventional internal combustion engine. U.S. Pat. No. 5,261,238 injects water only after combustion has been initiated within a cylinder and uses the heat produced to convert injected water into steam so as to increase the force produced by the power stroke. The invention of U.S. Pat. No. 5,125,366 also discloses the use of additional compound cylinders which are powered by the expanding exhaust gases and steam generated within the power cylinders. Neither of these inventions makes use of carefully controlled combustion outside the cylinder to produce steam for injection into the cylinder, as does the instant invention.
U.S. Pat. No. 5,191,766 makes use of heated exhaust gas to produce steam, which is then used to operate a power takeoff mechanism, such as a turbine. This power take-off mechanism is used to augment the power supplied by internal combustion. The invention does not make use of the steam to power the engine directly.
U.S. Pat. No. 4,023,367 discloses a steam engine which is made more efficient by using waste heat to preheat air entering the steam generation mechanism. However, this invention separates the steam generation and combustion processes so that no additional power is derived from the combustion process itself.
The present invention overcomes the problems presented by the above-mentioned references. In addition, the instant invention provides the benefits of high torque at low speeds, running more quietly than conventional internal combustion engines, since all combustion occurs outside the cylinder in a carefully controlled, non-explosive fashion.